(19)

(11)

EP 2 279 326 A1

(12)

(43) Date of publication: 02.02.2011 Bulletin 2011/05 (21) Application number: 09733534.3 (22) Date of filing: 17.04.2009

(51) International Patent Classification (IPC):  E21B 43/24(2006.01) (86) International application number: PCT/US2009/040932 (87) International publication number: WO 2009/129448 (22.10.2009 Gazette 2009/43)

(84) Designated Contracting States: AT BE BG CH CY CZ DE DK EE ES FI FR GB GR HR HU IE IS IT LI LT LU LV MC MK MT NL NO PL PT RO SE SI SK TR Designated Extension States: AL BA RS (30) Priority: 18.04.2008 US 46172 (71) Applicant: Shell Internationale Research Maatschappij B.V. 2596 HR The Hague (NL)

(72) Inventors: CUI, Jingyu Katy TX 77450 (US) JOSHI, Mahendra, Ladharam Katy TX 77450 (US) WELLINGTON, Scott, Lee Bellaire TX 77401 (US) REYNOLDS, Michael, Anthony Katy TX 77450 (US) MILAM, Stanley, Nemec Houston TX 77055 (US) (74) Representative: Matthezing, Robert Maarten  Shell International Reseach Maatschappij B.V. Intellectual Property Services P.O. Box 384 2501 CJ The Hague 2501 CJ The Hague (NL)